The incident occurred in an Orange County courtroom in California on Wednesday afternoon.

Jeffrey Scott Jones (56) was rushed to hospital after the shocking incident, New York Post reports.

The Huntington Beach native and English teacher was accused of molesting and having sex with a teenage relative of his girlfriend in 2012 and 2013.

The defence had argued that the girl had lied to cover up the fact that she used marijuana.

However, the prosecution argued that the DNA evidence was conclusive.

The crime carries a potential sentence of 66 years to life in prison.

“Right after the judge asked if we wanted jurors polled, both attorneys said no, and then he took a razor out of his left pocket and slashed his throat,” prosecutor Heather Brown told City News Service.

“His head hit the table, and I thought he fainted. But then I saw the blood and the razor on the table.”

The defence attorney said they respect the jury's decision, but they believed there was reasonable doubt as to what occurred.

Authorities are now investigating how the man managed to bring a blade into the courtroom.